Power mechanism for steering apparatus and the like



Nov. 16, 1943. E. A. M MURTRY I ,33

POWER MECHANISM FOR STEERING APPARATUS AND THE LIKE Filed Aug. 21, 1941 2 She ets-Sheet l Nov. 16, 1943. E. A. McMuR'rRY ,3 4

POWER MECHANISM FOR STEERING APPARATUS AND THE LIKE I Filed Aug. 21, 1941 2 Sheets-Sheet 2 INVENTOR.

Fatented Nov. 16, 1943 rowan MECHAN arranaros Claims.

The present invention relates to a novel power drive unit'initiated by manual operation such as the rotation of the steering wheel of a power propelled vehicle for assisting the operator in steering the vehicle and thereby greatly minimizing and relieving the operator of the strenautomotive vehicle including trucks, busses, road.

ISM non s'rnnnnzo AND 'rnr: LIKE Edward A. McMurtry, Chicago, Ill. Application August 21, 1941, Serial No. 407,699

' ease of assembly,

and farm machines, various forms of tanlgs, and

the like, and in steering such vehicles. Applicant has therefore devised'the novel power unit herein disclosed which merely requires the operato'r to begin the turning movement, after which the power unit functions to continue turning ofv the wheels, the amount of turning, however,

being under the control of the operator for the reason that the power unit becomes inactive and disconnected when the operator ceases rotation of the steering wheel. This novel invention permits any such vehicle to be driven by a woman.

The present novel construction is in the form of an attachment which may be quickly and simply applied to substantially any form of standard steering mechanism, or which can be installed as initial or standard equipment on the vehicle. Thenovel construction is positive in action and is so designed and co-related with the normal steering mechanism that should, for any reason, the power unit fail, the steering mechanism may be controlled in the usual manner by manual operation. It is further positive in operation in that the power unit can operate only when the operator is manually turning the steering wheel, and is automatically disconnected when such manual turning ceases.

' It is a still further object of the invention to m vide a power unit so associated with the normal steering mechanism that the worm on the steering rod may be employed with the usual hand operated device, thereby decreasing the amount or angle of tuming required of the steering wheel. Thev power unit acts as a steering stabilizer dashpot and prevents all" wheel shimmy and other erratic movements resulting from road-shock and the like. l

of a greater pitch than those an alternate construction of Further objects are to provide a construction of maximum simplicity, efficiency, economy and repair and operation, andsuch further objects, advantages and capabilities as will later more fully appear and are inherently possessed thereby.

The invention further resides in the construction, combination and arrangement of parts illustrated in the accompanying drawings, and while there is shown therein a preferred embodiment, it is to be understood that the same is susceptible of modification and change, and

comprehends other details, arrangements of parts, features and constructions without departing from the spirit of the invention. In the drawings: Figure 1 is a view in side elevation of the novel control mechanism associated with the steering mechanism of an automotive vehicle, the forward end of the vehicle being shown in phantom outline.

Figure 2 is in vertical cross section tion, of the control mechanism 'a fragmentary enlarged view, part and power unit applied to the steering apparatus of an auto;

motive vehicle. Figure 3 is a view in the power unit.

Figure 4 is a view valve construction shown in Figure 3.

Figure 5 is a view'in perspective of the dual valve arrangement. I Figure 6 is a fragmentary view, part in vertical cross section and part in side elevation, of

power unitand control mechanism therefor. Figure 7 is an enlarged view in perspective of the'novel control member for the power unit.

Figure 8 is a diagrammatic view of the valve and power cylinder assembly of Figure 6.

Referring more particularly to the disclosure in Figures 1 to 4 of the drawings, the novel power unit and control mechanism is illustrated as assembled with the steering mechanism of a power propelled vehicle I. Such vehicle is shown as equipped with a steering wheel 2 mounted upon thefixp per end of a steering rod or shaft 3 which may be enclosed within the usual steering post.

Mounted adjacent the lower end of this steering shaft is a .worm 4 keyed, pinned, or otherwise secured to the rod and in continuous meshing engagement with a gear segment or toothed member 5 secured upon a stub shaft 6 shown as formed with a squared or polygonal end extendand part in side eleva-' vertical cross section' through a novel valve construction employed in in front elevation ofthe ing rod 9 for stee ing to the exterior of a housing section 1. Mounted upon the external end of this stub shaft is a lever arm 8 connected at its lower end to a steerring and controlling the positioning of the front wheels ill through a steering knuckle I l in a manner well known in the art.

Secured upon the steering rod 3 within the housing section I 2is a sleeve or collar l3 shown worm when turned in one direction will frictionally clutch one of the collars l6 between the collar or sleeve I 3 and the inner bearing element 20, while the thrust of the worm in the other direction will frictionally clutch the otherof said collarslS between the collar or sleeve l3 and the inner element 20 of the other bearing retainer.

It is, of course, understood that these collars I6 are normally free upon the steering rod 3 and one only rotates therewith when the thrust of the worm 4 is such as to cause clutching engagementpf said collar. 3 I

In order that this clutching engagement may initiate and control the power unit,each collar I6 is provided with a peripheral groove or recess 2| for thereception of a split ring 22 having an upward and inwardly projecting portion 23.

-These split rings are preferably of a resilient material so constructed and arranged as to frictionally engage in thegrooves 2| with suflicient tension that movement of either collar will cause it to carry along the split ring until an abutment is placed in the path of the ring.

Suitably mounted uponthe housing section l2 are a pair of valve assemblies 24 and 25. Each is provided with a stub shaft 26 upon which is secured a depending arm 21. Each arm is bifurcated at its lower end28 for the reception of the inwardly projecting portion 23 of the split ring 22 in such manner that should either of the collars'lB be clutched to rotate with the steering shaft upon theoperator manually turning the steering wheel2, carry with it the projecting end 23 and rotate the arm 21 in a manner more clearly shown in Figure 4 of the drawings. Provision is made for limiting the are through which the arm 21 and consequently the split ring 22 rotate. For such purpose a pair of stops in the form of pins or other abutments 23 project from the valve housings 24 and 25 into the pa'thof movement of the arm 21. A spring tends to" return this arm to its normal, inoperative position.

As more particularly shown in Figures 3 to 5 or the drawings, the valve units comprise a valve 3| secured upon thestub shaft 26. Each valve is provided with an arcuate slot 32 adapted to communicate between adjacent passages from the tubes or conduits 33, 34 and 35. Each tube or conduit 33 is connected toacommon lead 33, which in turn is connected to asource of fluid supply such as compressed air or other available fluid, including vacuum from the manifold, oil, etc., while each tube 34 supplies the fluid to the opposite ends of a common cylinder 38, and each tube or conduit 35 provides an exhaust passage 75 rotation of the split ring 22 will the arm 21 connected to the valve 24 is rotated through an are permitted by'the stop pins 29, that is to the position as clearly shown in Figure 4, the arcuate slot 32 in the valve 24 would bridge the respective conduits 33 and 34 and fluid under pressure would flow from the conduit 33 and to and through the conduit 34 and passage 34',-into the cylinder 36 to the rear of the piston 31, thereby forcing this piston and its connecting arm 33 to the left as viewed in Figure 2 of the drawings,

to thereby automatically apply power to boost.

and continue turning of the steering mechanism as desired and controlled by the operator. When the steering wheel is rotated in the opposite direction, valve 25 is similarly actuated and fluid is forced into the opposite end of the cylinder 33 through the lead 34*, the piston being moved in the direction opposite from that above referred 'to. However, prior to the opening of the valve 25, valve 24 is closed so that the fluid at the right hand of the cylinder 36 (see Figure 2) is exhausted back through the lead 34- and exthe piston the inner walls 01" haust tube 35.

As stated above, this power control is initiated by the manual turning of the steering wheel 2 which applies a thrust upon the worm wheel 4 and its associated steering shaft or rod 3 to thereby frictionally grip one or the other of the collars l6 between the fixed collar or sleeve l3 and the inner face 20 of a bearing retainer l'l. Immediately upon the operator manually stopping the rotation of the steering wheel 3, the respective collar l6 which was previously rotated with the collar or sleeve I3 is positively released from its clutching engagement, and the spring 30 will simultaneously move the arm 21 to its normal or oil position. This movement of the arm 2'! in turn rotates the valve 3| to the oil position, thereby causing the arcuate slot 32 in the valve 3| to bridge the passage between the conduit leading to an end of the cylinder 33. and the exhaustconduit 35 to thereby relieve 31 of the fluid actuating pressure.

In Figures 6 to 8 is shown an alternate construction employing but a single valve in which the valve initiating mechanism is similar in construction and operation to that ures 1 to 5 inclusive, and like reference char- 'acters have been applied to such parts. In this latter form of the invention, a valve mechanism 39 as shown in Figures 6 and 8 is provided. This valve is actuated by a stub shaft 40 extending to the exterior of the valve housing, and upon The depending end 42 of this arm extends downwardly between the inturned ends or prgections 23 of the split rings 22. Thus, whichever.split ring is rotated byits' respective collar IS, the arm 4| will be moved in or rotated thereby an amount determined by the stops 43 projecting into the path of the projecting ends 23, and a stop 43 extending in the 41' at the upper end of These stops 43 are the arm or lever ,41.

the housing section 44/ In employed in Figpath of the projection secured to and project from order'that the arm I is returned to its normal, inoperative position when the operator stops manual turning of the steering wheel, a spring 45 is provided. This spring is shown as wrapped around the stub shaft 40 with the free ends engaging spaced inwardly projecting stops 46,- one of which is carried by the arm or lever ti and the other by the valve casing.

Figure 8 shows the valve construction with the valve tl secured upon the stub shaft 40. This valve is provided with arcuate slots t8 and 49 so disposed that fluid entering at M may pass from this inlet port through the port iii to the inlet port 52 of the cylinder 38, or pass through the port 53 to the inlet port 56 at the other end of the cylinder. In this form of valve asv in the dual valve arrangement, means is provided for positively moving the piston through fluid pressure in both directions so that the wheels may be turned in either direction. An exhaust port 55 leads to the atmosphere 'or wherever desired so as to prevent locking of the steering mechanism in any position of movement.

I claim:

1. Power mechanism for augmenting the man ual turning movement in either direction of ually controlled steering apparatus and the turning the steering apparatus in either direction.

8. A reversible power mechanism for assisting the turning movement of manually controlled apparatus including manually rotatable shaft and a worm secured thereon and subjected to an end thrust each time that the operator rotates the shaft, compris." g a pair of members normally loose upon the shaft but adapted to he clutchedfor rotation therewith each time the worm is subjected to an end thrust. an independently operable split ring associated with each collar and rotatable therewith, and a power unit connected. to the manually controlled apparatus and including valve mechanism actuated by turning movement of each split ring like and in which said apparatus is.provided with a steering shaft, a worm fixed thereon and subjected to a thrust when manually rotated in either direction, a tooth member in mesh with said worm and a connection from said member for turning the wheels of a vehicle, comprising a pair of collars loose upon said shaft but adapted to be clutched thereto upon the application of thrust to said worm, a valve connected to each collar and responsive to thrust in but one direction, and a power unit associated with and controlled by said valves and connected to the steering apparatus for relieving the operator of the manual effort and physical fatigue encountered in steering a power propelled vehicle; I

2. A reversible power mechanism for assisting the turning movement of manually controlled steering apparatus and the, like, and in which said apparatus is provided with a steering shaft and-a worm fixed thereon and subjected to a thrust when manually rotated in either direction, comprising a pair of collars loose upon the shaft, thrust bearings adjacent said collars, one of "said collars being adapted to be moved into contacting engagement with its adjacent thrust bearing" and rotate with the worm when the latter is subjected to end thrust, a valve connected with each collar, means for limiting the rotation of said collars and valves, and power means actuated by said valves for assisting the manual turning effort. by the ioperator when whereby to apply power to assist the turning movement in either direction, means for limiting the turning movement of the split rings, and

means for automatically and positively disconnecting the power unit upon the operator ceasing turning efiort in either direction.

to A reversible power mechanism for assisting the turning movement of manually controlled steering apparatus and the like and in which the apparatus is provided with a steering shaft 61 a worm fixed thereon and subjected to a thrust when manually rotated in either direction, comprising power means for assisting the manual turning eflcrt by the operator when turning the steering apparatus in either direction, a pair of control members loose upon the shaft but either adapted to be clutched thereto, a power control valve actuated by one of the controlmembers for causingthe power unit to operate in one direction'and an independent power con- 'trol valve actuated by the other control member for causing the power unit to operate in the opposite direction.

5. Power mechanism for augmenting the man- "ual turning movement in either direction of manually controlled steering apparatus and the like and in whichthe apparatus is provided with a steering shaft, a worm fixed thereon and sub jected to a thrust when manually rotated in either direction, a tooth member in mesh with the worm and a connection from the member for turning the wheels of a vehicle, comprising a pair of control members loose upon the shaft but either adapted to be clutched thereto upon the application of thrust to the worm, a doubleacting control valve actuated in one direction by one of the control members and independently actuated in the opposite direction by the other control member, and a power unit actuated by the control valve for assisting the manual turn- 1 ing effort by the operator when turning the steering apparatus in either direction.

- EDWARD A. McMURTRY. 

